The invention relates to an apparatus for retracting tissue, tissue parts, organs, bones, or other body parts during surgical procedures on human or animal bodies, with a holder for fastening clamps (or the like), the holding arm having holes at prescribed intervals, and the clamps having a shaft that can be inserted into the holes of the holding arm.
In surgical procedures, the organ being treated is exposed by clamps at the edge of the surgical opening to hold fast the interfering tissue situated above the organ. These clamps are often also referred to as leaves and, depending on the application, are blade- or spoon-like plates or hooks. To perform different surgical procedures on different bodies, clamps of different form are always required, and these are fastened to the holder in the position and attitude that is best for the particular procedure.
U.S. Pat. No. 4,852,552 discloses a retraction device for retracting ribs and their surrounding tissue to expose the heart for a surgical procedure. As already described, the clamps are fastened to a holder, which is seated on a toothed rack and which can be fixed in several positions. A clamp is rotatably fastened to the holder by a screw connection, and is fixed in the desired position by another screw. Significantly, the retraction device requires that each clamp be fastened, locked in place, and loosened individually by a screw connection.
U.S. Pat. No. 5,503,617 describes a retractor endoscope for minimally invasive surgical procedures. An operating device is situated at one end of a rigid frame. A removable clamp is fastened at the other end to a rotatable clamp holding arm by a dovetail joint. A clamp holding arm is likewise rotatably fastened to a second frame, which can move relative to the rigid frame. A clamp is fastened to the holding arm by a dovetail joint. The two clamps can be adjusted independently of one another. At least one of the two clamps has a device for fastening fiber-optic light guides to illuminate the surgical opening.
German application DE 91 00 113.7 discloses a spreadable retractor at each of whose ends which are situated opposite the handle is fastened a replaceable clamp by a spring snap lock.
German application DE 77 05 768 U1 discloses a rapid action snap lock for clamps, to which one or more bearing pins with grooves are fastened. These are placed into receptacle holes provided for them in a frame, a rod, or a holding arm. When the bearing pin is inserted into the receptacle holes, a ball latches into the groove through the spring pressure created by a leaf spring or coil spring.
DE 197 08 587 C1 discloses a detachable holder for a bladexe2x80x94also referred to as a clampxe2x80x94at the holding arm of a surgical retractor. A vertical slot and a slot slanted relative to the edge are machined into the holding arm. Two pins with a circumferential groove are disposed on the blade, and these can be inserted into the slots of the holding arm with a form-fit interlock. A blade is first inserted with a pin into the slanted slot, and is then turned about this pin, which acts as an axle, such that the other pin latches into the other slot. So the blade does not accidentally loosen from the holding arm, a flexible detent device is situated at the vertical slot of the holding arm. A ball is guided in a bore which leads laterally into the vertical slot of the holding arm, and this ball is pressed by a coil spring against the pin that is seated in the vertical slot. The other end of the bore is closed by a screw, against which the coil spring is supported. When the pin is swung into the slot with the detent device, the pin snaps into the slot behind the ball, and is pressed by the ball against the end of the slot. To remove the blade from the holding arm, the operator must overcome the force that the coil spring exerts on the pin.
A first disadvantage of this known holder is that the detent device, including of the bore, the ball, the coil spring, and the locking screw, requires a complicated and expensive manufacturing process.
A second disadvantage is that the detent device can become non-functional through contamination of the bore, the spring, and the ball.
A third disadvantage finally is that the detent device cannot be cleaned, unless the locking pin, the spring, and the ball are disassembled, cleaned individually, and then reinstalled, which takes some time.
An object of the invention to provide a retraction device that includes clamps that can be quickly and reliably fastened, loosened and replaced, and also fixed at various positions/attitudes.
In one embodiment, the holding arm is designed as a rod with a hollow space, within which a blade-shaped locking bar is guided. The locking bar has notches that have substantially the same spacing as the openings in the holding arm, and which expose the openings in the holding arm in the unlocked state, while, in the locked state, the notch-free areas of the locking bar partly cover the openings in the holding arm, and in that the locking bar can be pushed into a groove of the shaft, so as to fasten the clamps or the like on the holding arm.
In a second embodiment, a long hole whose width is less than the diameter of the opening, follows each opening whose end is followed by a depression, whose cross section is the same as the cross section of the opening, and in that the shaft of the clamp is designed as a T-shaped head, whose larger cross section corresponds to the cross section of the opening and the depression, and whose smaller cross section corresponds to the width of the long hole, so that the T-shaped head of a clamp can be inserted into the opening, can be moved in the long hole as far as the depression, and can be lowered into the depression, and in that a locking bar on the backside of the holding arm can be inserted into a rail guide so as to fix the T-shaped head in the depression.
To install, remove, or replace a clamp, the locking bar is brought into the unlocked position where its notches are aligned with the openings of the holding arm. In this state, the clamps can be removed from the holding arm and inserted in the holding arm by placing the shafts of the clamps into the holding arm. Furthermore, the clamps can be turned into the desired attitude. They are locked by moving the locking bar from the unlocking position into the locking position, so that the locking bar slides into the groove of each shaft of a clamp, and in this way fastens the clamp and at the same time locks it in place. The locking bar can be secured against opening, with a locking device (e.g., a screw connection).
Advantageously, the clamps can be fasted to the holding arm, locked in place, and again loosened at the same time by a small movement of the locking bar.
To fasten a clamp on a holding arm, with the second inventive solution, the T-shaped head of the clamp is placed into the opening. Then the head of the clamp is moved along the long hole, at the end of which it is pressed into the depression by pulling on the clamp. To lock it, a locking bar on the backside of the holding arm is placed into a rail guide. The locking bar holds the head of the clamp in the depression.
The opening, the depression, and the T-shaped head of the clamp preferably have a circular cross section. The diameter of the opening, the depression, and the large diameter of the T-shaped head of the clamp have the same size, while the smaller diameter of the head of the clamp corresponds to the width of the long hole.
The cross sections of the opening, the depression, and the head of the clamp need not be circular. For example, they can be triangular, rectangular, diamond-shaped, square, hexagonal, etc. They only need to have the same shape, so that the head of the clamp can be inserted into the opening with a positive form fit, can be moved in the long hole, and can be lowered into the depression.
One clamp may have for example two T-shaped heads. The rail guide for the locking bar, which presses the heads of the clamps into the depression, preferably includes a T-groove. The locking bar may have, for example, accommodations for surgical instruments, which are preferably bores. The clamps and the T-shaped heads may for example be made of one piece. Alternatively, the heads also can be welded to the clamps.